The quick coupling can be coupled with another coupling, and the reciprocal locking is obtained in general through a ring nut supported by the female coupling. In the disconnected condition the coupling normally has the obturator in the closing position of the passage which only opens by effect of the engagement between the couplings.
Couplings of this kind are designed to allow engagement between couplings even when there is a fluid under pressure in one or both of them.
One of the drawbacks that may sometimes arise in couplings of this type consists of the fact that it may be very difficult to make the engagement if during penetration between the male coupling and the female coupling one of the two opens before the hydraulic seal has been established with the other one.
This circumstance may cause a flow inversion and flow rate peaks to arise that hinder the correct engagement between the couplings with a consequent leak of fluid that may also cause pollution for the surrounding environment.